Air nozzle and ionizing unit for electrostatic air filters



' Filed Jan. 15, 1950 Feb. 12, 1952 G. F. LANDGRAF 2,585,138

AIR NOZZLE AND IONIZING UNIT FOR ELECTROSTATIC AIR FILTERS 2SHEETS--SHEET 1 HI". 1. 11h '5 nllh ll E George ELandgraf BYM al/WC- H/SATTORNEYS Feb. 12, 1952 F. LANDGR'AF 2,585,138

AIR NOZZLE AND IONIZING UNIT FOR ELECTROSTATIC AIR FILTERS Filed Jan.13, 1950 2 SHEETS-SHEET 2 INVENTOR.

George E Landgraf m: u 6m J HIS ATTORNEYS Patented Feb. 12, 1952 AIRNOZZLE AND IONIZING UNIT FOR ELECTROSTATIC AIR FILTERS George F.Landgraf, Pittsburgh, Pa., assignor to Trion, Inc., McKees Rocks, Pa.,

of Pennsylvania a corporation Application January 13, 1950, Serial No.138,355

' 1 Claims. (01. 1837) This application relates to an air nozzle andionizing unit for electrostatic air filters, particularly air filters ofthe type having an ionizing unit and a collecting unit which areseparately mounted in a housing and which may be separately removed forpurposes of maintenance and repair. The air nozzle and ionizing unitwhich I have invented combines in one structure a specially designed airnozzle and an ionizing unit which can readily be installed and removedfrom the front of the housing as a single structure. The air nozzle isdesigned to prevent blow-by and at the same time it provides a supportfor the ionizing tubes of the ionizing unit. It also carries supportsfor the ionizing wires which are spaced between the tubes.

In the accompanying drawings I have illustrated a present preferredembodiment of my invention, in which- Figure 1 is a plan view of myunit;

Figure 2 is a rear elevation view;

Figure 3 is a front elevation view;

Figure 4 is a section along the lines IV-IV of Figure 2;

Figure 5 is an end view;

Figure 6 is a fragmentary plan view similar to Figure 1 but on anenlarged scale;

Figure 7 is a section along the lines VII-VII of Figure 4 but on anenlarged scale; and

Figure 8 is a vertical section through one of the ionizing tubes alongthe lines VIII-VIII of Figure 7.

An electrostatic air filter of the type for which my invention isintended has an ionizing unit which charges solid particles carried bythe air as it first enters the filter and a collecting unit whichremoves the charged solid particles from the air before the air leavesthe filter. The ionizing unit comprises a row of tubes spaced parallelto each other across the front of the filter and a series of ionizingwires extending between and parallel to the tubes. A large potentialdifierence is maintained between the wires and-the tubes. The collectingunit comprises a series of plates spaced parallel to each other acrossthe housing of the filter so that all air which enters the filter passesbetween the plates after it leaves the ionizing unit. A high potentialdifference is maintained between alternate plates, and the chargedparticles in the air are attracted to and remain on the plates fromwhich they are washed at intervals. As stated above I have invented anair nozzle and ionizing unit which can be assembled in the front of thefilter and removed from the unit as a single unit. This obviouslyfacilitates maintenance and repair.

Figure 3 shows the front of my unit which comprises a rectangular frame9, ionizing tubes 10, and ionizing wires i I. As shown in Figures 1 and2 flanges I2 and I3 extend from the top and bottom inner edges of theframe in the direction of air flow through the unit and also slopeinwardly to slightly restrict the air passage, that is, the flange I2slopes slightly downwardly and the flange l3 slopes slightly upwardly.Flanges l4 and I5 extend in the direction of the air flow from the innerside edges of the frame and (as shown in Figures 1 and 6) also slopeinwardly to slightly restrict the air flow. At a point approximately inline with the ionizing tubes N3, the flanges I4. and ['5 are curvedoutwardly and in effect form two additional ionizing tubes. From Figures1 and 2 it will be noted that all of the air which enters through theframe 9 passes between tubes and wires or between the curved sideflanges l4 and I5 and the wires. This avoids all blow-by. In otherwords, all of the particles in the air passing through the filter aresubjected to the high electrostatic field maintained between the wiresand the tubes. If desired a hum suppressor" l6 such as described in mycopending application Serial No. 72,885 filed January 26, 1949, can beaddedv to my unit to prevent howling of the ionizing wires in dryweather.

Figures 2, 4 and 5 show the structure for supporting the ionizing wiresH. The frame 9 carries two insulators I! above the top flange l2 andspaced adjacent each end of the flange and two insulators l8 below theflange l3 and spaced adjacent each end of the flange. The insulators 11support a top bar 19 which is in the form of an angle bolted to theinsulators and the insulators [8 support a bottom bar 20 which is alsoin the form of .an angle bolted to the insulators.

The bars [9 and 20 have a series of holes spaced along their length. 8hooks 2| are placed in the openings in the top bar 19 and a loop isformed in each ionizing wire and passed over an S hook. Small springs 22are hooked at one end into the openings in the bottom bar 20 and thebottom of each ionizing wire is looped to engage the other end of one ofthese springs, the springs thus serving to hold the wires taut.

Figures 6, '7 and 8 show the structure for supporting the ionizing tubesIll. The flanges 12 and [3 are scalloped to provide clearance for theionizing wires. The widest portions 23 of the flanges terminate intongues 24 which extend into slots cut in the tubes I0 and are bent overas shown in Figure 8 to lock the tubes in posi- From the foregoing itappears that my air nozzle and ionizing unit is relatively simple toconstruct because few assembly operations are involved. The air nozzleprevents blow-by. It also supports the ionizing tubes and wires so thatthe entire unitcan be installed as a unitary structure in an air filterand easily removed for maintenance and repair.

While I have described a present preferred embodiment of my invention,it isto be understood that it may be otherwise embodied within the scopeof the following claims.

I claim:

1. An air nozzle for electrostatic air filters having an ionizing unithaving two sets of electrodes, one set being charged oppositely to theother set comprising a rectangular frame having a rectangular openingtherein, and flanges extending in the direction of air flow from theedges of the frame forming-said. opening, two flanges on opposed sideshavingameans for supporting between them one set of. electrodes of theionizing unit, the two other sides sloping inwardly from the front ofthe frame-and then curving outwardly at a point substantially in linewith the electrodes carried by thefirst said flanges.

2. An air nozzle for electrostatic air filters having an ionizing unithaving two sets of oppositely charged electrodes, one set comprisingtubes, the other set comprising wires, said nozzle comprising arectangular, frame having a rectangular opening therein,, and flangesextending in the direction of airflow from the edges of the frameforming said opening, two flanges on opposed sides having tonguesadapted to extend into slots in tubes of the ionizing unit and therebysupport the tubes, the two other sides sloping inwardly from the frontof the frame and then curving outwardly at a point substantially in linewith the tubes.

3. An air nozzle for electrostatic air filters having an ionizing unithaving two sets of oppositely charged electrodes, one set comprisingtubes, the other set comprising wires, said nozzle comprising arectangular frame having a rectangular opening therein, and flangesextending in the direction of air flow from the edgesof the frameforming said opening, two flanges on opposed sides being scalloped -toprovide clearance for ionizing wires of the ionizing unit, the portionsof said flanges furthest from the frame terminating in tongues adaptedto extend into slots in tubes of the ionizing unit and thereby supportthe tubes, the two other sides sloping inwardly from the front of theframe and then curving outwardly at a point substantially in line withthe tubes.

4. An air nozzle and ionizing unit for electrostatic air filterscomprising a rectangular frame having a rectangular opening therein,flanges extending in the direction of air flow from the edges of theframe forming said opening, two opposed flanges having means forsupporting tubular electrodes of the ionizing unit, a bar mounted on therear side of the frame adjacent each flange which supports the tubularelectrodes but electrically insulated therefrom, and wire electrodessupported by the bars extending between the ionizing tubes and sideflanges and parallel thereto.

5. An air nozzle and ionizing unit for electrostatic air filterscomprising a rectangular frame having a rectangular opening therein,flanges extending in the direction of air flow from the edges oftheframeforming said opening, ionizing tubes supported by 'said flanges,ionizing wires extending between and parallel to the tubes and sideflanges, and supports for said wires mounted on the rear, sides of saidframe but electrically insulated therefrom.

6. An air nozzle and ionizing unit for electrostatic air filterscomprising a rectangular frame having a rectangularopening therein,flanges extending in the direction of air flow from the edges of theframe forming said opening, ionizing tubes extending across the frameand parallel to each other, said tubes having slots adjacent each end.two flanges on opposed sides'sloping inwardly and having tongues adaptedto extend into said slots to support the tubes, ionizing wires extendingbetween and parallel ,.to the tubes, insulators mounted on the rear faceof the frame adjacent to but spaced from the flanges which support thetubes, and bars mounted on the insulators and supporting the ionizingwires.

'7. An air nozzle for electrostatic air filters having an ionizing unitone set of electrodes of which are tubes, said nozzle comprising arectangular frame having a rectangular opening therein, and flangesextending in the direction of air flow from the edges of the frameforming said opening and sloping inwardly, two flanges on opposed sideshaving means for supporting between them tubes of the ionizing unit, thetwo other sides sloping inwardly from the frontof the frame and thencurving outwardly at a point substantially in line with the tubes.

GEORGE F. LANDGRAF.

REFERENCES CITED The following references are of record'in the file ofthis patent:

UNITED STATES PATENTS

